Waterfox is an open-source web browser based on Mozilla Firefox for 64-bit Windows and macOS systems.

Waterfox (64-Bit) version of Firefox. The Firefox source code is taken and compiled to run specifically for 64-Bit Windows computers. To make Waterfox stand out a bit more, it' s compiled with optimizations so that it will run more efficiently and faster than just compiling Firefox as a 64-Bit program. Waterfox was the first community Firefox builds to release a 64-Bit version of Firefox 4 when it first came out.